Lamp changing apparatus



May 1, 1951 Filed Oct. 5, 1946 J. R. MaCKAY 2,551,028

LAMP CHANGING APPARATUS 8 Sheets-Sheet l lll May l, 1951 J. R. MaCKAY2,551,028

LAMP CHANGING APPARATUS Filed Oct. 5, 1946 8 Sheets-Sheet 2 May 1, 1951R MaCKAY 2,551,028

LAMP CHANGING APPARATUS Filed 00T.. 5, 1946 8 Sheets-Sheet 3 7072 2iILIVIfu-Iiag/ A( May 1, 1951 J R, MaCKAY 2,551,028

LAMP CHANGING APPARATUS Filed OCt. 5, 1946 8 Sheets-Sheet 4 May 1, 1951l J. R. MaCKAY 2,551,028

LAMP CHANGING APPARATUS Filed Oct. 5, 1946 8 Sheets-Sheet 5 May 1, 19518 Sheets-Sheet 6 Filed Oct. 5, 1946 J. R. MaCKAY LAMP CHANGING APPARATUSMay 1, 1951 8 Sheets-Sheet 8 Filed Oct. 5, 1946 Eig. Il

vorey Patented May l, 1951 LAMP CHANGING APPARATUS John R. MacKay,Packanack Lake, N. J., assignor to Wallace & Tiernan Products, Inc.,Belleville, N. J., a corporation of New Jersey Application ctober 5,1946, Serial N0. 701,429

13 Claims.

My present invention relates to lampchanging apparatus for automaticallyreplacing an electric lamp which has failed. The invention, while havinggeneral utility, has been made especially for beacons, such as aviationand marine beacons, or other signal devices using comparatively highwattage lamps, which are successively positioned with their centers ofillumination at a predetermined point. This point is usually the focalpoint of a lens or lens system, such as a Fresnel lens or other opticalapparatus, and wherein the space requirements permitting the interchangeof lamps is such that a peculiar and novel type of lamp interchangingmeans is desired in order to adapt the lampchanging apparatus to a lenssystem which is of minimum size permitting lamp interchange.

The invention aims to provide an improved lampchanging apparatusespecially suitable for the uses aforesaid, which shall be ofcomparatively simple and rugged construction and very reliable inoperation; which shall function to replace a failed lamp rapidly and toposition a new lamp accurately; which shall eiect the replacementoperation smoothly and without harmful jarring and which shall maintainthe positioned lamp accurately in position regardless of vibration andother causes of damage.

Considering the invention from the point of View oi its use with aFresnel lens system, a minimum size lens system permitting theinterchange of large wattage lamps such, for example, as LPS-52 envelopelamps, and also PS-40 envelope lamps, requires that the inside diameterof the lens system be slightly more than twice the outside diameter ofthe lamps to be used therewith, so as to permit one lamp to be withdrawnfrom its operative position while another lamp is being moved to itsoperative position in accordance with the present invention, otherwiseit would be necessary to move the lampchanger apparatus, or the lenssystem, or both, bodily, which is undesired in a practical installation.The provision of a lampchanging apparatus which will eiect the abovepurposes by moving the lamps to and from their respective operativepositions is a primary object of the present invention.

Among the further and more detailed objects of the present invention areto provide lampchanger apparatus as aforesaid, wherein at least twolamps are mounted upon a rotatable carrier and are moved, primarily bythe rotation of that carrier and secondarily by a movement in respect tothe carrier under control of a cam system, to eiect the desired resultsaforesaid. In this con- (Cl. 24U-37.1)

nection it is a detailed object of the invention to provide aninterchangeable cam having cani surfaces respectively arranged forassociation with each of at least two lamps as aforesaid, and whereinthe coniigurations of Ythese cam surfaces are determined by taking intoaccount the space requirements or restrictions upon movements ofl theparts, and the dimensions of the lamps in question as to shape and size,so as to effectv the desired results aforesaid.-

A further specific object of the invention in connection with the aboveis to provide means by which the lamps are positively prevented frombeing moved in such manner as to engage or collide with one anotherduring lamp interchanging movement,` while still operating in a systemhaving minimum dimensions as aforesaid.

A further specic object of the invention is to provide lampchangingapparatus wherein the actuating energy for lamp interchange is derivedfrom a potential energy storing means, such as a'spring or weight, andwherein there is an escapement means to limit the rate of movement oflamp interchange to a safe value, while permitting rapid resetting ofthe apparatus to its initial position withoutv regard to movement ortime requirements therefor of the escapement mechanism, which is`normally employed during the automatic vlamp interchange.

Further detailed objects of the invention in this connection are toprovide for the elimination of friction in an automatic release meansfor the lamp interchange mechanism, so as to insure satisfactoryoperation underV severe conditions to which the mechanism may be subjectin use, and wherein maintenance is relatively infrequent due to theinaccessibility of some of the places where devices of the kind hereindisclosed may be installed.

A further object of the present invention is to provide modiiied formsof means in respect to that above generally referred to for affording apeculiar and novel type of non-parallel movement as between the lampbases and the lamps themselves on the one hand, and the lamp carrier onthe other hand. The purpose of this is to provide for the adaptation ofstandard types oi lamp carrier mechanisms used on commercial lampchanging devices to enable them to accommodate extra large lamps of thetypes known as Pis-40 or PS-52 above referred to. When these extra largelamps are used with certain now standard lamp changing equipment, it hasbeen .found that they will interfere with the movements of thisapparatus due to their large size. However, by relatively simple changesin the equipment in accordance with the present invention, it can bemade usable with these special lamps by providing a non-parallel motionmechanism between the carriers and the lamps, so that as the carrierrotates, the lamps are not held permanently vertical or at any other oneangle, but their angle is progressively varied in response to therotation of the carrier. The provision of such an apparatus, whileconstraining the lamps to movement in a single Vertical plane, istherefore a further detailed object of this invention. p l

Other and more detailed objects of the present invention will becomeapparent from the following description of preferred embodiments thereofand from the appended claims, when considered in connection with theaccompanying drawings, in which:

Figure l is a view principally in elevation, but with a Fresnel lensassociated therewith in vertical section, showing certain parts of thelampchanging apparatus in its normal position in full lines and at anintermediate position in dotted lines;

Fig. 2 is a similar view of most of the apparatus of Fig. l on a largerscale to show some of the details thereof;

Fig. 3 is a view of the parts taken from the rear in respect to thedirection in which they are shown in Figs. l and 2, illustrating theactuating mechanism inside the case with the cover removed;

Fig. 4 is a view similar to Fig. 3, but taken at right angles thereto.with the case in vertical section, but parts contained thereinsubstantially in elevation;

Fig. 5 is a View substantially in horizontal section on the line 5-5 ofFig. 2 showing the internal construction of the hub portion of the lampcarrier;

Fig. 6 is a detailed sectional view on an enlarged scale takensubstantially on the line 6-5 of Fig. 2;

Fig. '7 is an enlarged fragmentary detailed view illustrating theescapement mechanism and the pawl and ratchet devices associatedtherewith, taken substantially on the line l-l of Fig. 5.

Fig. 8 is a fragmentary detailed View in vertical section showing theescapement mechanism and drive therefor, taken substantially on the line8 8 of Fig. 5;

Fig. 9 is a diagrammatic view illustrating the wiring diagram' andelectrical connections for Y" the apparatus and certain of themechanical actuating means substantially in perspective showing themechanical and electrical operation of the entire apparatus;

Fig. l0 is a view partly in elevation and partly in vertical section ofa modied form of the invention; and

Fig. 1l is a diagrammatic view of the form of the invention shown inFig. l0 in conjunction with a lens system and illustrating variouspositions of the parts incident to the movement thereof.

The apparatus of my present invention is in elfect an improvement onthat shown in my prior Patent No. 2,289,315, granted July 7, 1942,entitled Signal Device in that it includes all, or substantially all,the desirable characteristics of that device and in addition providesseveral novel features including a lampchanging apparatus which canaccommodate itself to the handling Qi.

larger size lamps with a minimum size of lens system due to certainpeculiar and novel structural provisions hereinafter particularlydisclosed.

While it is possible to provide a lampchanging system where there aremore than two lamps and to provide means whereby when each lamp insuccession burns out or otherwise fails, the next lamp in succession ismoved intov position to replace the failed lamp, I have chosen toillustrate the present invention as applied to an apparatus whereinthere are but two lamps, one being a principal or working lamp, which isnormally at a position such that its center of illumination will loe ata preedtermined point, which is usually the focal point of a lenssystem, such as a Fresnel lens l, and the other, a spare or auxiliarylamp for use in the event that the principal lamp fails. As shown inFig. l, a principal lamp 2 is at its operative position in which itscenter of illumination is located at the point 3' which is at the focalpoint of the' lens i. At this position, the auxiliary lamp designated aiis in effect out of any position wherein it will interfere with theeffective use of the principal lamp 2.

It is desired, upon the failure of the lamp 2, to move it to aninoperative position and to move the lamp 4 to a position such that itscenter of illumination will be at the point 3, and particularly toeffect this movement in such a way that the lamps 2 or 6l will not bepermited to Contact with any part of the lens system l or with eachother during their movement. To effect this result, the lens system musthave an inside diameter slightly more than twice the outside diamter ofthe lamps 2 and ll, so the lamps 2 and i may be able to pass one anotheras in the positions shown in dotted lines in Fig. l. Such an operationis unattainable with any mechanism or apparatus to be found in the priorart to the best of my knowledge, as in most such prior art structuresthe lamps are moved about a single xed center or by a straight parallelmotion device asi shown, for example, in my Patent No. 2,289,315, thelatter device being preferable but still requir-r ing a lens system ofgreater diameter than that required in accordance with the presentinvention. It is desired that the lamps be carried upon a single lampcarrier structure which in the present instance is generally designatedat 5, and which is, in accordance with the present invention, rotatableabout a substantially horizontal axis in respect to a suitable support.It is necessary in eecting the desired results cf the present inventionto control accurately the angular position of each of the lamps inrespect to the lamp carrier or, from a broader point of view, to controlthe relative positioning of each lamp in respect to the carrierthroughout its movement. This control is preferably peculiar to eachlamp and so constructed and arranged, as by the inclusion of a cammechanism designed for the particular size and shape lamps to beemployed, that the desired general results above set forth will beattained.

In conjunction with the above, there must be means for controlling theposition of each lampA accurately at its operative position, forcontrolling the position of the carrier at each of its'l positions atwhich a lamp is located at its operative position, for actuating thecarrier to move it from its normal to its auxiliary position in theevent of failure of the principal or working lamp shown at 2 to itsother terminal position, and to PlFOVde. i0? the resetting of theapparatus upon the replacement of the principal lamp, in addition toother electrical and mechanical means for carrying out the aforesaidgeneral purposes. These means will be described in detail hereinafter.

Turning now more particularly to the accompanying drawings, andespecially to Figs. l to 5, inclusive, thereof, there is provided asupporting structure here shown as a case 5, which may be a suitablemetal casting and which may be secured in any desired manner, as bybolts l, passing through slots or elongated operings 8 (Figs. l, 2 and5) formed in lateral extensions of the case 5, to any suitable supporthere generally designated at 9, which be any structural part on whichthe apparatus may be mounted. A set up adjustment of the position of thelamps in a direction perpendicular to the plane of the paper (Figs. land 2) may thus be effected by adjusting the entire device in thisdirection and securing the adjustment by the bolts l.

The case may be provided with a suitable cover if: secured thereto as bya plurality of screws Il in the form of nuts threaded on bolts I2. whichare suitably, rigidly secured in parts rigid or integral with the caseit `The parts 5 and lil thus provide a hollow chamber in which most ofthe electrical and mechanical actuating means for the device may beenclosed as best shown in Fig. 4.

suitably supported in the case is a sleeve member I3 (Fig. 5) whichpasses through a hole in a boss i4 and has a iiange bearing against theouter end of this boss. The member I3 is nonrotatably secured inposition by a nut I5 threaded on the end of the portion of the member I3extending inside the case 6 as shown. This secures the member I3non-rotatably to the case B and serves to determine the axis of rotationof the lamp carrier 5 concentric with the axis of the member I3.

Turning now to the construction of the lamp carrier or carrier structure5 per se, this carrier comprises a pair oi similar cross arm members l5and il which are provided with apertures at their mid-point to surroundportions of the sleeve member i3. These members are connected togetherby a hub structure including a pair of annular members i3 and I9 whichmay be secured together by a sleeve welded or otherwise secured to themembers i8 and I9. The members i? and I9 are connected together by aplurality of bolts 2i and the members it and I8 by a plurality of b -ts22, as shown (Fig. 5). Suitable bearing sleeves, as shown at 23 and 24may be interposed between the inside of the central openings of the armsle and l 'I and adjacent portions of the sleeve member I3 to minimizefriction. These bearing members are preferably of the selflubricatingtype such as metal-impregnated graphite, which is also preferably usedfor all bearings liable to be subjected to the heat of the lamps so asto provide the necessary lubrication without the use of ordinarylubricants, which tend to become gummy in use at the temperaturesexistent. The lamp carrier 5 is prevented from axial movement upon thesleeve member i3 by reason of the member 23, which is rotatable with thecarrier 5 and which bears against the outer end surface of an annularflange forming a part of the boss lil of the case 6. Outward movement ofthe carrier 5 is similarly prevented by a portion of the arm 6surrounding the central opening therein bearing against a flange 25 ofthe sleeve member i3 as best shown in Fig. 5.

Eachv of the lamps 2. andV 4 is supported by the lamp carrier structure5 at a point spacedfrom the center of rotation thereof by the samepredetermined amount, these lamp supporting means being essentiallysimilar to one another so that only onewill be described in detail.

Referring now principally to Fig. 4, a movable lamp supporting means251m the form of a substantially U-shaped bracket is provided havingintegral or rigid pivot pins or projections 21 and 28 thereon. Thesepins or projections are shown as formed with a larger diametercylindrical portion fitting inbearing apertures near the ends of thearms l5 and il and smaller diameter concentric pin portions extendingtherefrom for purposes hereinafter set forth. It will be understood thatthe pins or projections Zland 28 are in axial alignment with oneanother, so that in practice each lamp is rotatable in respect to thecarrier 5 about a horizontal axis which is parallel to the horizontalaxis of the carrier itself. The lamps as shown are located atdiametrically opposite points on the carrier 5. Each of the lampsupporting means 25 is arranged to support a Suitable socket 29, whichmay be of any desired commercial type suitable for the type lamps to beused and which is in turn suitably secured to a base plate 35i in anyusual or desired manner. The plate lf is supported from the means 26preferably at three equidistantly spaced points by an adjustable springdevice formed as by providing threaded pins lextendingdcwnwardly fromthe plate 35i and passing through suitable bosses 32- to receivethereunder suitable nut or lock nut means helical compression springs 34being provided about each of the pins 3I between the underside of theplate 3Q and the inside of the bosses 32 Thus, by suitable adjustment ofthe nuts 33 on the pins 3l, the position of the lamps, particularly todetermine the respective operative positions thereof, can be accuratelyand finely adjusted in directions both in and perpendicular to the planeof the views shown.

Means are provided, preferably including cam means peculiar to each ofthe lamps 2 and il, for independently controlling their angularpositions in respect to the carrier 5. For Vthis purpose there isprovided a plate type cam 35, which is stationary but removably andinterchangeably mounted upon the supporting structure, in this case-uponthe case 5', by means of a plurality of screws as shown at 35 which passthrough the cam and are threaded into bosses formed on the outside ofthe case t as bestshown in Fig. 4. As shown in Figs. l and 2, theright-hand side of the cam 35 is formed with a cam surface 31 forcontrolling the position of the lamp 2 while the left side has a surface38 for controlling the position of the lamp Cooperating with these camsurfaces areV followers respectively associated with each lamp, thesefollowers comprising rollers sand arms ls, the latter of which aresuitably secured at their upper ends, as by a suitable set screw ortaper pin, to the smaller diameter portion of the pins 23 extendinginwardly from the arm I6 (to the left as seen in Fig. 4).

En order to retain the respective cam rollers against the cam surfaces3l' and 38, means are rovlded, preferably including mechanicalinterlocking means and a spring means, which are interconnected betweenthe two lamp supporting structures for reasons appearing hereinafter.rEhese means include an arm 4I, secured as by a set screw to theoutwardly extending, small diameter portion of' each ofthe pins 2l, thelower ends of the arms di being connected together by means includingshackle portions i2 pivoted to the arms 4| and rods 63 threadedthereinto by adjustable amounts and a barrel spring device generallyindicated at 44, this device being shown in detail in Fig. 6. As shownin that figure, the right-hand rod 43 is threaded in one head i5 of thebarrel spring device lili, this head being in turn threaded on acylinder or sleeve portion 45 thereof, which has threaded on itsopposite end a head 4l, the parts 135 to 41 in practice being rigid withone another. The left hand rod 43 as seen in Figs. 1, 2 and 6 passesloosely through the head il and has secured thereto intermediate the endof the sleeve member d@ and the inside of the head 45 a loosely fittingpiston head 48. Interposed between the inside of the head 4'! and theleft side as seen in Fig. 6 of the head 38 is a helical compressionspring 49. The maximum possible movement of the left rod d3 with respectto the right rod "it is limited by the mechanical dimensions of theparts as shown in Fig. 6 to a distance between the end of the sleeve itshown at the right and the inside of the head 45.

From the above, it Will be seen that the spring 49 tends to draw thelower ends of the two arms 4I together and thus tends resiliently toretain the cam rollers 39 in engagement with their respectivelyassociated cam surfaces 3l and 38. Thus under normal conditions thelamps 2 and i will be positioned as determined by the shapes of thesecam surfaces and the angular position of the lamp carrier 5. These camsurfaces are so shaped in conformity with the size and shape of thelamps themselves and with the available space within the lens system,and further with the position of the point 3 (Fig. l) that at theinitial position of the carrier 5, the lamp 2 will be positioned asshown in Fig. 1 with its center of illumination at the point 3. Slighterrors in the positioning of this lamp may be compensated for bysuitable adjustment of the nuts 33 on the pins 3i associated with thislamp. The cams are further so shaped that as the lamp carrier 5 moves inrotation, as hereinafter set forth in detail, the lamp 2 will be movedangularly from the full line position (Fig. 1) through the dotted lineposition and the lamp .f5 from its full and through its dotted lineposition, so that the lamps will be moved in a manner as not to contactwith each other or with the parts of the lens system. However, if meanswere provided for springing each of the lamps independently toward itscontrolling cam 3l and 38 respectively, there might exist some factorwhich could cause the lamps to engage one another incident to theinterchange, causing a breaking of one or both of the lamps themselvesor possibly other parts of the apparatus. In order positively to preventthis, the means 42 to 49 is provided wherein the lamp supports areinter-connected together and are prevented from rotary movement inrespect to the carrier 5 to such an extent that either lamp can engagethe other, this movement in practice being limited by limiting themovement of the piston head 48, as hereinabove described to the spacebetween the right end of the sleeve 4S as seen in Figure 6 and theinside of the cap or head 45. Thus there is provided a means forpositively and mechanically preventing the undesired action otherwisepossible. Nuts 50 threaded on the rods t3 may be loosened to permitadjustment of these rods in respect to the shackle means 2, these nutsbeing tightened to secure the adjustment when made. This is normallyused as a set-up adjustment in conjunction with the other partshereinabove described to determine the limits of the spring device toeffect the results above described and desired.

Means are provided tending continuously to rotate the lamp carrier in adirection to move the working lamp out of its operative position and theauxiliary or spare lamp i toward its operative position. Such means inthe present instance preferably includes a potential energy storingdevice, which from a broad point of view may be a weight or a spring. Inaccordance with the present invention it is preferred to use for thispurpose a helical torsion spring, which is so located and protected inthe device that it may be permanently lubricated. To this end there isprovided a spring 5i Fig. 5) which is located inside the sleeve portion2G forming a part of the hub of the lamp carrier 5. One end of thespring 5i is secured in a suitable springend-receiving aperture 52formed in a part of the ange 25 of the sleeve member i3, and` thusnon-rotatable with the lamp carrier. The other end of the spring iii isreceive-d in a suitable bore or other spring-end-receiving aperture asshown at 5d in the outer arm il. inasmuch as the spring 5i is entirelyenclosed as shown, the space surrounding this spring may be providedwith a suitable lubricant of a type which will be relatively permanentduring the operation of the device, this spring and its lubricant beingprotected by the construction shown from ingress of dirt or othercontamination and also being prevented from being dried out by the heatgenerated from the large lamps used.

Means must now be provided for determining the initial or normaloperative position of the parts at which the lamp 2 is at the positiondescribed and shown in Fig. 1 and for controlling the speed of movementof the lamp carrier during its movement to a position such that thespare lamp is at its operative position, and further for determiningthat position. For this general purpose, there is provided a gear trainand an escapement mechanism which will now be described.

suitably secured to the inside of the lamp carrier, as by a plurality ofscrews 5d (Fig. 5), is a large ring gear 55, see also Figs. 4 and 9,this gear thus being rigid with the lamp carrier 5. Arranged to mesh'with gear 55 is a pinion 56 mounted on a shaft iii which passes throughthe inside wall of the case E and through an instrument or mechanismpanel 58 of suitable insulating material, secured` to the case 5 inspaced relation thereto and alsopasses through a pair of spaced gearhousing plates iid and fifi. The panel 58 is suitably secured by screws,some of which are shown at iii (Fig. 3) to bosses, one of which is shownat 52 (Fig. 4), the bosses preferably being integral with the case t.The plates 59 and 6@ are suitably secured together in predeterminedspaced reiation to one another1 and to the panel 58 by bolt and spacermeans generally indicated at 63. Just inside the plate 5i! as shown, theshaft 5'. carries secured thereto as by a suitable set screw, Fig. 7, agear Gli, which meshes with a pinion 55 rigidly carried by a shaft 56which is journalled in the plates 59 and 69, as best seen in Fig. 8.There is thus a direct drive between the lamp carrier through gears 55and 56 to shaft 5l, and thence thro-ugh gears 64 and @5 to the shaft ii.Also carried on the shaft $6 in a manner to be freely movable in respectthereto is a wheel t?, the periphassigoee 9 ery of which is serrated asshown for engagement with a pair of pins 68 on a wobble member 69 whichis secured to a shaft 'Hi also journalled in the plates 58 and 6D.

As will later appear in detail, during the normal operation or movementof the lamp carrier from the position shown in Figs. l and 2 to itsposition in which the spare lamp 4 is v,at the operative position of thelatter, the wheel 67 is retained rigid with the shaft 66, so .thatrotation of this wheel and hence angular vmovement of the lamp carrieris controlled as to speed by the vibration of the wobble member @9. Tothis end, means are provided which ineffect constitute a unidirectionalclutch drive device between the shaft 55 and the wheel 39, -so that uponmovement of the lamp carrier 5 for Vthe automatic interchange of lamps,the wheel` 6l will be rigid lwith the shaft 66, while permittingresetting of the lamp carrier manually when a new working lamp 2 is putin position by force applied to the lamp carrier itself as hereinafterset forth and without requiring the movement of the wheel 57 or thewobble member 6B, which would have the result either of slowing uptheresetting operation or of breaking the parts, both of which resultsareundesired. For this purpose is preferred to provide a sort of freewheeling arrangement for the resetting operation, permitting rapidresetting movement of the carrier with little or no movement of thewheel 6l' and the wobble member E9. While various types of mechanismscould be provided to accomplish these results, I prefer to accomplish itby providing a pair of pawls 'Il which are pivoted on the wheel Si, atpoints offset from the shaft E6 and which cooperate with a ratchet 'i2secured to shaft 5S, the pawls being suitably spring pressed toward theratchet as shown. Thus during the automatic lampchanging movement, theshaft the ratchet if, and thezwheel El will rotate in acounter-clockwise direction as seen in Fig. without relative movement;while on the resetting movement, the ratchet 'I2 may rotate clockwisewithout rotating the wheel El, the pawls sliding over the teeth of theratchet in the usual way.

This resetting movement is effected in practice by means mechanicallyVengaging the lamp carrier 5. In View of the relative inaccessibility ofthe parts, the arm I6 of the lamp carrier is extended out in one or bothdirections beyond the azi-m il thereof, and has provided adjacent-to itsends perforations shown at 13 (Figs. l to 4). In practice it iscontemplated that an operator may reach down through the lens vHi with along wire having a hook on its lower end, engage the hook in the lowerperforation 13 and. draw up on the wire, so as to move the lamp carrierlangularly about its center until it reaches a point at or slightlybeyond that at which the working lamp 2 is at its operative position, asseen in Fig. l.

This movement may be limited by a suitable stop indicated at i4 (Fig.2), which is formedv as a fixed abutment arranged to engage one side ofthe arm i5 at a point in the movement of that arm slightly beyond theposition thereof shown in Figs. l and 2. The actual operating positionof the parts at their operative positions shown in Figs. l and 2 isdetermined by other means hereinafter described.

rl"he other end of the movement of the lamp carrier is preferablyaccurately determined by a 10 stop means similar to stop 14 in certainrespects and including a projection 'l5 through which is threaded a stopscrew'TB, which may be accurately adjusted to a predetermined positionandthe adjustment secured by a lock nut 71. This screw is in such aposition that the upper right hand end thereof, as seen in Fig. 2, Willengage against a part of the arm I6 at the desired terminal position ofthat arm at which lamp 4 is at its desired operative position with itscenter of illumination at the point 3, Fig.4 l.

V'lhe parts n4 to T! are secured to a stop plate means which is carriedrigidly by the case 6 and projects through a central opening in the cam31 formed for this purpose.

Means are provided for supplying current to each lamp when `it is inoperative position. For this purpose there is provided on the panel 58adjacent to the bottom thereof, as seen in Figs. 3 and 9, a pair. ofbinding posts 18 and 19, which arearranged to be connected to suitablesource of power as generally indicated in Fig. 3. In the event thatdirect current is used, the binding post 1B is indicated as theVpositive terminal, and 19, the negative terminal. The apparatus is alsoarranged, as hereinafter more particularly set forth, for use withalternating current and further is arranged for use with lamps havingdifferent watta'ges. As shown, the positive terminal I8 is connectedthrough lines and 8| with lamps! and 4 respectively. The other lines tothese lamps, i. e., to the sockets 29 in which these lamps are held,being shown at 82 and 83 respectively and being connected to fixedcontacts 84 and-85 respectively of a pair of cam operated switches. Themovable contacts of these switches shown at 86 and 87 respectively Yarecarried by spring strips of good conducting material shown at B8 and 89respectively, which have associated therewith spring members 9S and 9 Iwhich are respectively arranged to be engaged alternately by a suitablecam indicatedat 92. The lower ends of the members' and' 89 are suitablysecured in bracket members 93 and 94 which are independently carried bythe vpanel 58, this panel being o fl insulatingmaterial such as BakeliteThe switch contacts and 8'! are connected toone another asindicated-diagrammatically in Fig.` 9 by the lines 95V and 9S, thisconnection in practice being between the bracket members 93 .and 94 byva strip as indicated at 91, Fig. 3. This common connection is thenconnected through a line including a flexible portion as indicatedat 98,Fig, 3, and a'correspondingly numbered line in Fig.y 9 selectively toeither one of a pair of binding posts 99 and ft, the connection asactually shown in the drawings being to the binding post l. The purposeof this ris to vcompensate for different size lamps as to ratedcapacity, an indication of this rating being given in Fig. Y3, whereinthe binding post 99 is designated to be for 500 or4 750 watts andbinding postl for 1,000 or 1,500 watts. The purpose of thisconipensation is not concerned with the operation of the relay alone,but is to prevent an abnormal voltage drop across the relay winding,coil 10|, which wouldresult in a lowered Voltage at the lamp and areduction in light output. Binding posts 99 and |59 are connected byshort leads to'diferent points on a magnet coil It! substantially asshown, the other end of this magnet coil being connected by a line' ft2to a binding 'post H33 which in turn is connected by a leadf 'i104 tobinding post-79. The lines' 80,"82, 8! and" 83 are of heavy butilexiblewire so as to permitf the movement of the carrier 5, while beingdirectly connected at each end as shown. These wires preferably extendfrom the inside of the case t through the sleeve member i3, and aresuitably insulated by enclosing each wire in a plurality of bead membersof porcelain or other insulating material as shown.

r'he cam 92 is rigidly mounted upon a shaft H35 which passes through thepanel 58 and the rear Awall of the case B and has secured rigidly therenis rigid with the rotary lamp carrier, these pins y projecting to theleft therefrom as seen in Fig. 4, i. e., toward the case so as to engagethe outer 'portion of the lever arm |06. This lever arm is normally heldin a given position by friction, so that no spring or other means isusually provided tending to turn it in either direction.

In the position of the parts shown in the diagrammatic Fig. 9 and alsoshown in Fig. 3, the lever arm Hit is substantially vertical, at whichposition the cam 92 is in engagement with the spring member Sic causingit to move the member 88 to the left to close contact members Bt and S6.This isthe condition of the parts during the time in which the principallamp 2 is lighted. If this lamp should fail for any reason and the lampcarrier be rotated so as to bring the lamp i into operative position,the nal portion of the rotative movement of the gear 55 would cause oneof these pins, say the pin lill', Fig. 9, to engage the left side of thelever it@ as seen in that gure, so as to rotate the shaft iil throughabout 90 and so as to move the cam 92 clockwise, as seen in Fig. 9, toopen the circuit through the lamp 2 by separating the contacts dit and8% and to close the circuit through the lamp by causing the engagementof contacts '85 and 8l.

It will now be seen that the circuit through either of these lamps maybe traced as follows, from the positive terminal is through the linesSil or 3 i, the socket and lamp in operative position, thence to theswitches through the lines 82 or t3 and the switches Sli-8d or 85-31,thence by the lines 95-96 or the connector 971 and the line 98 to thecoil ll, thence through the lines 02 and liifi to the negative terminal19. It will be seen from the above that the magnet coil lili will alwaysbe in series With an operating lamp, so that irrespective of whether D.C. or A. C. current is used, the armature associated with this magnetcoil as hereinafter described will be attracted thereby during theperiod of usefulness of the operating lamp. Preferably one of the polepieces of the relay magnet is provided with shading coils, which may bein the form of one or more copper slugs, discs or washers in or aroundthe magnetic path so that the relay will operate on A. C. currentwithout excessive vibration of its armature H5. In the event that aflasher device is used, the flasher may be interposed between the sourceof current and the terminals 'it or l, or both, so that no action cantake place irrespective of the deenergization of the coil I0! ashereinafter set forth during intermittent periods of darkness if aflashing light is to be employed.

Provision is made, as hereinafter set forth, to release the lamp carrier5 for the interchange of lamps if the operating lamp 2 fails during atime period in which current is being supplied to the terminal 'F3-T9.For this purpose, a second magnet coil or motor relay, generallyindicated at m9, is provided, which is normally deenergized and which isconnected to be energized only when series coil lili is deenergized andduring a time period in which current is being supplied to the terminalsH8-19. The terminal 'i8 is connected by a short line Hi] to one terminal2t! of a selenium rectifier unit IH. lThis rectier comprises two opposedsections 202 and 2d?. having a common connection or terminal 2G63. Whendirect current is applied to the terminals 'iS- 79 of the lampchanger,current flows from the terminal 'i8 through the conductor llc, onesection 202 of the rectier l i l, a conductor i i2 from the commonterminal 2M of the rectifier to the left end as shown of the winding 25Mof the motor relay H39, thence through switch contacts 2&5 of the switchoperated by the series relay Mil (assuming no current is iiowing throughthe lamp 2 and the series relay mi because of a burnout), thence throughconductors Mii and ldd to the terminal i9 and the other side of thedirect current line. The other end. of the section 2% of the rectier isconnected to the right hand terminal H4 as shown of the winding 2234i bya conductor H3. No current flows through the section ZES of the rectieri i i during this period as its polarity is opposite to the polarity ofsection E92 and also opposite to the polarity of the line current.Energiaation of the winding Zilli results in the attraction of thearmature l il of the motor relay It, thereby permitting rotation of thespring driven lamp carrier as hereinafter set forth. When the spare lamp4 approaches its operating position, the contacts Si and 35 of the camoperated switch close and current now commences to flow through theconductors 8i and 83, the former spare lamp Il, switch contacts and 3l,the flexible lead Qt, and the winding of the series relay lill, andthrough the conductors H12 and Mill to terminal 19. Energization of theseries relay iti causes the opening of its contacts 205, whereuponcurrent ceases to flow through the section 202 of the rectier. Upon theopening of these contacts, the magnetic field of the motor magnet m9(winding 2M) collapses, causing the production of a counter-E. M. F. inthe winding 23d; and as this momentary voltage is of opposite polarityto that of the normal line current, it is dissipated through the section23 of the rectifier iii, rather than across the now opening contacts2235 of the series relay, thereby greatly reducing the tendency for anarc to form at that point.

When alternating current is applied to the terminals i8 and 'i9 of thelampchanger (and a lamp il is in the process of being carried into focalposition), the positive alternations of the current pass through thesection 2E? of the selenium rectifier and the winding 2431i of the motorrelay in the circuit as previously described for D. C. operation. Thisresults in the flow of a pulsating direct current in the relay winding20d. At the end of each pulsation of current, i. e., during eachnegative alternation (60 times a second if 60-cycle alternating currentis used), the eld of the motor magnet tends to collapse and cause acounter-E. M. F. to be developed in its winding 2M, which tends tooppose to some extent the normal flow of current through that winding.However, through the medium of s'ection 203 of the Vrectii-ler thiscounter-E. M. F. is dissipated and results in a greater flow of currentthrough the winding 204 of the motor relay and a stronger attraction ofits armature I than would otherwise take place. Furthermore, upon theopening of the contacts 205, effected by the energization of the seriesrelay IOI and the movement of its armature H5 to the full line positionshown in the drawings, this section 203 of the rectier also performs itsfunction of preventing the formation of an arc at the contacts 205. Thearmature |I5 of the relay |0| is connected to the body portion of thisrelay by a at spring 20B, which serves not only as a flexible hinge, butalso as a spring tending to move the armature ||5 to the left as seen inFigs. 3 and 9 to close the contacts 205.

The movable armature of the motor relay is in eiiect pivoted to the lefthand end support for the coil as seen in Fig. 9 in any suitable manneras by providing pins rigid with the coil support passing through holesin the armature with a sloppy fit. A suitable tension spring I I8 isprovided, tending to hold the armature in its upper position, exceptwhen the coil is energized. The armature Ill has rigidly secured to itsupper portion a U-shaped bracket member I9 carrying a roller |20 whichis arranged when the armature is at its upper position as shown, thecoil |09 being then deenergized, to be in line with a part carried bythe mechanical train which moves with the lamp carrier. In this case,this part comprises a radially extending pin |2| eX- tending from a hubof the gear t4. When the coil its is energized, the armature I|`|thereof is moved downwardly against the tension of the spring H8, thusmoving the roller |20 out of the path of the pin |2i, this movementbeing substantially frictionless due to the provision of a roller as at|20 instead of a solid or non-rotatable abutment.

The series relay, comprising the magnet coil Ii and the armature I I5,is of the low reactance, quick acting type, whereas the motor relay |09,comprising the winding 204 and the armature lll, is of the highreactance, slow acting type.` Because of this fact, and the momentaryheavy inrush of current due to the low resistance of the cold lamplament, the contacts 205 carried by the series relai" lill, between thearmature II5 and the terminal |241, are operated very rapidly when therelay coil I0| is energized; and because of the high reactance andinertia of themotor relay, |09, no appreciable current flows throughthese contacts, nor does the motor relay tend to attract the armature ieven though the current to the lampchanger is periodically interruptedby means of a flasher mechanism, which may cause frequent but momentaryclosure of the series relay contacts 205.

Considering now the operation of the device as a whole and starting withthe operation of resetting the lamp carrier after a good bulb has beeninserted for use as the operating lamp 2, force is applied manually tothe lamp carrier 5 to move it to the position shown in Figs. 1 to 3.This force serves to increase the potential energy stored in the spring5I and the movement resulting from this force being continued until thelamp carrier arm I6 engages the stop 'I4 at a point somewhat beyond thedesired point. Assuming at this time that current is being supplied tothe binding posts '|8'|9, when the carrier is moved to this terminalposition, the switch cam 02 will be positioned by the pin |08 in theposition shown in Fig. 9, so as to engage switch contacts 84-85. At thistime the lamp 2 will be lighted by a current flowing therethrough andthrough coil |0| in series therewith. When the mechanical force on thelamp carrier 5 is released, the spring 5| will move the lamp carrieruntil the pin |2| engages the roller |20, the motor relay |09 being atthis time deenergized due to the fact that the series relay coil |0I isenergized to open the switch controlled by its armature II5. Thisdetermines the normal operative position of the parts, i. e., theposition at which the pin 52| will engage against roller |20.

If now the operating lamp 2 burns out, the relay itl is deenergized,permitting the closing of the switch controlled by its armature I5 andcontinuously energizing the relay |09 until relay lill is againenergized. This, however, cannot happen until the lamp carrier hascompleted its movement, when upon the nal portion of the lamp carriermovement, the pin |53?, Fig. 9, will engage the lever |05 to move thecam 92 to a position to connect contacts 85 and 3l. Meanwhile, the relay|09 is continuously energized so as continuously to attract its armatureil and hold it in the lower position, at which the roller i20 is out ofthe path of the :pin IZI. In a practical embodiment of the invention,the gear (i4 with which the pin |2i is associated makes about threerevolutions during the lamp carrier movement, that movement as to thecarrier 5 being substantially less than The terminal position of theparts resulting from this movement however is not controlled by themeans within the case 6, but rather by the set screw it, Fig. 2, whichis in a position to engage a part moving with the lamp carrier, i. e.,the arm l thereof. This position is accurately adjusted and set by theset screw l5 and the adjustment secured by the lock nut l?. At thistime, the carrier will have turned to such a point that cam 02 willconnect contacts 85 and 87 which completes a circuit in series throughthe lamp ll and the coil I0! and opens contacts 84 and 3S. Thus even ifa portion of the filament of the lamp 2 formerly in position were bysome vibration or otherwise to contact again so as to make a shortcircuit within the lamp, this action would have no harmful effect as thecircuit through this lamp is now broken at the contacts te and 86. Thespare lam-p t is now in its operative position and acircuit is completedtherethrough so that the apparatus will operate until such time as thespare lamp also burns out.

ln order that an operator or maintenance man, possibly at some distancefrom the light system itself, may be apprised of the fact that theoperating lamp 2 has burned out, so as to be able to take the necessarysteps to replace it, means are provided, arranged to be associated withany suitable alarm system. F'or this purpose, the shaft |55 carrying thecam S2 is also provided with an eccentric or cam 22, arranged to beassociated with a plunger |23 of a conventional type of microswitch |24.This switch has leads |25 and Hit connected to binding posts I 2l andi23 which may be suitably connected to any desired type of alarm system(not shown). It is assumed that the alarm system will include anysuitable source of E. M. and any suitable type or types of alarm meanssuch as a light, bell, or otherwise.

Turning now to the form of the invention shown in Figs. l0 and ll, thereis illustrated in. part a lamp changing apparatus arranged to be appliedto a type of structure as particularly shown in' my prior Patent No.2,289,315 granted July 7, 1942. The primary difference, however, betweenthe present arrangement and the patented structure is that in thepresent arrangement the lamp carrier is intended for rotation onlythrough a limited arc ci not over about 180 and in addition the lampsare not maintained Vertical, yas in the patented disclosure referred to,but are progressively tilted While maintaining them in the same plane.So, for example, a lamp |29 in moving from its operative position shownin full lines in Fig. 11 will move through an intermediate positon shownin dotted lines at I3@ to a nal inoperative position shown indot-anddash lines at |32, the longitudinal axis of this lamp beingprogressively changed from the vertical at the operative position of thelamp to the position shown at |3|. At the same time the other lamp shownat |32 in full lines in this figure moves through an intermediateposition in dotted lines at |33 to a position coincident with that shownfor the lamp |29. The angle of the longitudinal axis of the lamp |82with respect to the vertical progressively moves toward Zero .as thecarrier is moved in the lamp interchange operation. This is necessary,for as seen best in Fig. 10, the lamps |29 and |32 are so large thatthey could not be held vertically at their inoperative or lowerpositions as shown in l0, as they would engage the holder portion of theother lamp. By the provision of this special angular movement whilemaintaining the lamps generaliy vertical, I am enabled to use a carrierwhich is substantially the same as that shown in prior patent and thusminimize the number of diiferent types of structures which need bemanufactured for accommodating diiferent sized installations.

Referring now more particularly to the drawings, the stationary supportfor the lampehanging device is shown at |3113, this structurecorresponding to the structure iii of my prior patent. Rigidly mountedin this support is a stationary stud |35 about which a lamp carriergenerally indicated at |3|i may rotate, the axis of the stud |35 beinghorizontal, as shown.

The carrier |36 may be rotated by any suitable means (not shown), forexample, means such as are shown in my prior patent, but not here shownin detail, such means being in general indicated by a ring gear E37secured to the carrier and meshing with a pinion |38, which may besuitably connected to a driving mechanism. Il? then any well-known typeof free wheeling device be arranged in conjunction with the drivingmechanism, so as to permit manual resetting of the carrier |3|5` afterit has been moved through an angle .of 180, such as a friction clutch ora pawl and ratchet device as shown at M -"i2, Fig. 7, the .carrierdriving means of my prior patent aforesaid may be adapted for thispurpose. On the lother hand, any suitable spring-actuated means, such asthat particularly described in respect to the preceding figures andincluding a torsion spring as shown at 5|, Fig. 5, located at anyconvenient part of the device, or a weight-actuated mechanism asgenerally referred to hereinabove, may be employed in conjunction withan escapement means as particularly described above. It will beunderstood that as to this form of the invention, the specific type ofactuating means for the carrier is relatively immaterial.

Means are provided for stopping the rotative movement of the carrier ateach of its terminal positions, in this case at points 180 apart. Forthis purpose the carrier |36 is provided with a pair of pins 'H9-Mildiametrically disposed in respect to the carrier axis and arranged toengage the opposite sides of a ilapper lever |42, which is pivoted asshown at |52, Fig. 1l, and is adapted to be engaged by the pins. Thelever Eli is freely movable about its pivot. Movement of this lever islimited, however, by a pair oi adjustable stop screws m3 and Mii,threaded through suitable lugs carried by the support |34 and secured inadjusted position by lock nut means in a conventional manner. By theadjustment of these screws Hit and |44, the limits of the carriermovement may be accurately determined, so as to insure the correctpositioning of each lamp in the exact focus of any lens system withwhich the device is associated.

In the form of the invention shown the lamp carrier |36 carries rigidlysecured therein adjacent to its outer ends a pair of horizontallydisposed studs it which are secured to the carrier as by nuts MS.livoted about each of these studs is a lamp carrier casting itl. Thecasting ill has secured thereto a suitable lamp socket Ei and aninsulating block its carrying the contacts for 'transmission of electricpower to the lamp. Inasmuch as these parts it to |49 are the same forboth lamps, the same reference characters have been used for both.

Means are provided for rotating the castings ld? about the horizontalaxes of the studs incident to and proportional with the rotation of thecarrier |36 about its axis stud |35. In general, means similar to eitherof the arrangements shown in my prior patent could be used for thispurpose, that is, either a train of gears as particularly shown in Figs.l0 and l1 of the accompanying drawings, or sprocket and chain means asshown, for example, in Figs. 1, 2 and 4 of my prior patent abovereferred to. The essential characteristic is, that in accordance withthe present invention, a non-parallel linkage is provided, that s, onein which the longitudinal axis oi each lamp is not maintained vertical,but is progressively varied from the vertical as the lamp moves from itsoperative position and vice versa, the lamp in its operative positionpreferably being vertical, as shown.

In effecting this result in accordance with the present disclosure,there are provided one or more stationary gears |56, two of which areshown in the accompanying drawings, although but one need necessarily beused. These gears are splined to the stud it, so as not to rotate withthe carrier |36. Meshing with the gears |50 are a pair of idler gears|5| freely rotatable on axes carried lby the carrier |36. Meshing withthe idler gears il are gears i52, which are respectively rigid with andcarried by the castings |41, being secured thereto as shown by one ormore screws |53, Fig. 10. lf then the gears |52 are provided with agreater number of teeth than the gears |50, the results showndiagrammatically in Fig. 1l will ensue. The angle of the lamps to thevertical at their inoperative positions shown in full lines for the lamp|32, Fig. 11, and in dotand-dash lines at |3| for the lamp |29, willdepend upon the ratio or ratios of the number oi teeth of the gears |52in respect to the gear or gears tt, any desired ratio or ratios beingused within the purview of the present invention in order that therewill be no interference of parts incident to any possible movement ofthe lamp carrier |36.

It will be noted from the above that the lamps are always maintained ina single vertical plane aangereibythe movement of the carrier 136, butthat-they are moved in respect to the carrier in sucha manner that therewill be a substantial difference be tween the angle of the longitudinalaxis of each lamp in this plane at its operative positionoinV respect tothe angle of the axis of such lamp at its inoperative position. In thisrespect a some what similar result is attained to that disclosedY in theform of the invention shown in Figs.V 1-9 in that there the angle ofeach lamp with respect to the carrier and with respect-to the verticalis controlled by a cam surface, while as shownlin Figs. l and 11 thisangle is controlled-v bythe ratio of the number of teeth of a pair ofgears in a gear train.

The means shown in Figs; and 1l for coni-- ducting current to theseveral lamps. mayf be?l identical with that fully described in myprior.

Patent No. 2,289,315 above referred` to and. is,A

therefore, not particularly described herein, such'` means being ingeneral indicated. byV thelrefer` On the. other,` hand,z it.mayfv encecharacter |54. be desired to conduct current. to the lamps by permanentconnections similar to theVv arrangement disclosed in Figs. l-9 and inthe accompanying description hereinabove. SuchA an.- ar.- rangement isto be considered withinthe purview of this invention.

While I have shown anddescribed but atfew of the possible embodiments.of the. invention, vari!- ous additional variants havebeensuggestedsand:

others will present themselves to thoseskilledin..Y

the art. I do not wish tobe limited,.therefore,z except by the scope ofthe appended claims; which are to be construed validly,.as broadly asythe state of the prior art permits.

What is claimed is:

1. Lampchanging apparatus for use withaV Fresnel lens of minimum sizepermittinglamp. interchange and having a ,focal point,..compris;-` ing astationary support,v arotary lamp carrier.` mounted on said support formovement in re spect thereto about a substantially horizontall.

axis, means limiting the movementV ofsaidlamp:

carrier about its axis to less than 180, a-.pair of. 45;

electric lamps mounted on said carrier at. sub1 stantially diametricallyopposite pointsand-forr movement in respect thereto about horizontalaxes, each of said lamps having an axis of` sym'- metry and having adimension along said; axisi of symmetry greater than the distancebetween.,

said diametrically opposite points, an intere-` changeable stationarycam mounted on'said sup-- port adjacent to said carrier having;azcamsur= face respective to each of saidY lamps, camY fol-l lower meansrespectively associated with; said;A cam surfaces and arranged tooperate inV reevr sponse to movement of said'carrier torotate'said:lamps about said horizontal axes'in respect to. said carrier, said camsurfaces beingconstructed and arranged in conformity with theV sizeand.'r

shape of said lamps and the dmensions'ofthe;

associated Fresnel lens so as to control the moves ment of one of saidlamps from an operative po..-

sition wherein its center of illuminationis atrthezfocal point of saidlens to an inoperative position and to control the movement of the otherofsaid lamps from its inoperativeposition to an operative position inwhich its center of illumina-- tion is at the focal point of said lensbymoving;

said lamps through paths. such'V that they will: pass one another inspaced relation and will be; maintained out of contact withany--partloffsaid.;`

lens.

2..Lampchanging apparatusA inv accordance withl claim 1, wherein said'cam follower meansA are mechanically interconnected, so as positively toprevent saidV lampsA contacting one another during movement ofY sa-idcarrier and said lamps as aforesaidl 3. Lampchan'gingl apparatus,comprisingy a' sta-- tionary support, a rotary lamp carrier mounted onsaid support for movement in respect thereto about a4 predeterminedaxis; ay plurality of elecf tric lampsY mounted" onu said carrier for'move-Y ment in respect thereto about axes parallel to`v the first-namedaxis, means'formovingV saidcar-Y rieriin respect to-said support, astationaryV cam carried bysaid support adjacent to said carrier andhaving'a peripheral cam-surface respectivelyI associated witheach'ofsaid'lamps, a cam"fol'- lower respectively associated with' each of saidlamps andfsaid camsurface's forcontrollingitheangular position thereofin respectto said'car'f rier,v means including'a spring for urging both`said followers against' theirH respective surfaces" of said-"cam and:for' mechanically interconnecting'sai'd followersthroughsaidspring andmeans-y in such` mechanical interconnection" means' in-`V lcluding amechanical/stop for positivelyprevent'- ing suchangular movementofeither'ofA` said lamps as could'causesaid lamps to touch one*another-during themovement of said lampsinlcident' to4 the movement ofsaid;` carrier.'

4. Lam'pchanging apparahis; comprising a stationary support, a'rotarydamp carrieifstructureV Vvand -means `including -aunidirect-ion'alclutchhdrive device-interposedv in ysaid-mechanical`tra-inandeifectivesupon'- manual resetting-ofsaidcarrier to restoresaidfpotential energy@ storingy means to its initial physical conditionbyiorce'appliedto said .carrier for permittinga rapidresetting of-VVsaid carrier without requiring. movement -of.said escapement meansincidentA thereto.

5. Lampchangingapparatus iii-accordance withL claim 4,-Ywherein` saiduni-directional-clutch drive device-isa ratchet and-paw-l. mechanism.

6. Lampchanging apparatuslin-aecordance w-ithclaim 4,- wherein -saidrpotential energy storing; means -is a-helical torsion spring.-

7. Lampchangfing apparatus in accordancewitlri-A vrclaim 4, whereinsaidpotential energy storingI means is--a spring, and-comprising:infaddition:` meansforminga chamber'for containing saidispringfand alsofor conta-ininga lubricant forthe4m spring substantially permanentlysealed inv` saidi chamber, wherebyto vprevent. the spring from-` beingfouled byfdirt andtherlubricant from-being dried -out bythe heatVgeneratedby said lamps-J 8;* Lampchanging'apparatus in-accordance withclaim` 4, comprising inl addition a-'hollowv annularI drum forming alpart offsaid lamp`carrier=structure andrforminglaninternal chamber for're'ceiv`-vv ing a helical torsion-spring whichis=said poten tialenergyk storing,v means,..one.end.ofl said springl being secured to.ysaidrlamplcaririer structure andi the other lend Atola 0part? rigidswithsaidf supporti-r said chamber also providing an enclosure for containinglubricant for the substantially permanent lubrication of said springduring its operation.

9. Lampchanging apparatus, comprising a stationary support; a rotarylamp carrier structure mounted on said support for movement in respectthereto about a predetermined axis; a plurality of electric lampsarranged to be brought, by the movement of said carrier structure, toposition such that their centers of illumination are successively at apredetermined point; means for rotating said carrier in respect to saidsupport, including potential energy storing means constantly urging saidcarrier to rotate in a predetermined direction in respect to saidsupport, a mechanical train and an escapement means for limiting therate of rotation of said carrier as driven by said potential energystoring means, and means including a unidirectional clutch drive deviceinterposed in said mechanical train and effective upon manual resettingof said carrier to restore said potential energy storing means to itsinitial physical condition by force applied to K said carrier forpermitting a rapid resetting of said carrier without requiring movementof said escapement means incident thereto; means for stoppmg the rotarymovement of said carrier with one of said lamps in its operativeposition with its center of illumination at said predetermined point;and means subject to the burning out of the lamp in its operativeposition for automatically releasing said carrier for movement, by forcederived from said potential energy storing means, to a position suchthat a second lamp is at its operative position with its center ofillumination at said predetermined point.

10. Lampchanging apparatus in accordance with claim 9, wherein saidstopping means comprises a rigid abutment means and a roller, one ofwhich is carried by a member movable with said carrier and the other ofwhich is carried by said releasing means, said roller operating tominimize friction incident to the releasing operation.

1l. Lampchanging apparatus in accordance with claim 9, wherein the lasttwo named means including the stopping means and the releasing meanscomprise a pin projecting laterally from a rotating element of saidmechanical train, a magnet having a movable armature, a roller carriedby said armature in position when said magnet is deenergized to beinterposed in the path of said pin so as accurately to predetermine theinitial position of said lampv carrier structure with one lamp at itsoperative position with its center of illumination of said predeterminedpoint, and an electric circuit including a magnet operated switch ofwhich the magnet is in series with an operating lamp at its operativeposition and arranged upon cessation of electric current iiow throughsuch lamp to complete a circuit through the rst named magnet so as towithdraw said roller fromv the path of said pin and thereby to permitmovement of said lamp carrier under the influence of said potentialenergy storing means to move a second lamp to its operative position.

12. Lampchanging apparatus, comprising a thereto about horizontal axesarranged diamet-v rcally opposite one another on said carrier and atuniform distances from the axis of rotationthereof,y a stationary cam,removably and interchangeably secured to said support and havingperipheral cam surfaces on each side arranged respectively to controlthe positions of said lamps in respect to said carrier, lever arms andcam followers associated with each of said lamps for cooperation withthe respective cam surfaces of said cam, mechanical interconnectingmeans including a spring interposed between said lever arms and camfollowers for urging said cam followers against the respective camsurfaces and including means for mechanically limiting the angularmovements of said lamps toward one another so as positively to preventsaid lamps touching one another during movement of said carrier, saidcam surfaces and the movement of said carrier being conjointly soconstructed and arranged in accordance with the shape and size of saidlamps that at one terminal position of said carrier one of said lamps isat its operative position with its center of illumination atsubstantially a predetermined point, while at the other terminalposition of said carrier, the other of said lamps is at its operativeposition with its center of illumination at said point, while said lampsare moved to and from their operative positions in paths close togetherso as to enable the apparatus to be employed with a Fresnel lens ofminimum size permitting lamp interchange by the mechanical movement ofone lamp past the other; means for rotating said carrier in respect tosaid support including a helical torsion spring concentric with saidcarrier and disposed centrally thereof, said spring tending at all timesto rotate said carrier, a mechanical train and an escapement means forlimiting the rate of rotation of said carrier by said spring, and meansincluding a pawl and ratchet device interposed in said mechanical trainto permit the resetting of said carrier in its initial position againstthe action of said spring without requiring movement of said escapementmeans incident thereto; stop means for predetermining the initialposition of said carrier comprising a magnet armature having a rollerthereon interposed in the path of movement of a part moving with saidcarrier and included in said mechanical train, and an elec-tric circuitincluding an electro-magnet switch, the magnet of which is in serieswith a lamp in its operative position and operative upon the cessatationof currrent flow through such lamp for energizing the rst named magnetto withdraw said roller from the path of movement of movable parts ofsaid mechanical train, so as to permit of the movement of said carrierto bring the second lamp to its operative position while withdrawing thefirst lamp therefrom, and switch means actuated by movement of saidcarrier for cutting off electric current ow through the first lampremoved from its operative position and connecting the second lamppositioned at its operative position in the circuit.

13. Lampchanging apparatus for use with a substantially cylindricalFresnel lens having a focal point located substantially on the axis ofsaid lens, comprising a stationary support, a rotary lamp carriermounted on said support for movement in respect thereto about an axisperpendicular to the axis of said lens, two electric incandescent lampsmounted on said carrier, each of said lamps having a longitudinal axisof symmetry, at one point on which is a center of illumination of thelamp, mounting means for each said lamp pivoted to said carrier formove- 21 ment in respect thereto about an axis parallel to the axis ofsaid carrier in respect to said support, the mounting of said lampsbeing such that during movement of said carrier the axis of each of saidlamps is maintained in a plane including the axis of said lens, astationary cam mounted rigid with said support for each lamprespectively, cam follower means for each said cam, mounted on saidcarrier and connected to said lamps respectively for controlling therelative positions of each of said lamps in respect to said carrierduring the movement of said carrier, and means for rotating said carrierfrom one predetermined angular position in respect to said support toanother such position, said cams being so shaped and designed that saidlamps will just pass without contact with one another or with said lensduring movement of said carrier to move one lamp from'an operativeposition with its center of illumination at lthe focal point of saidlens to an inoperative" position and to move the other of said lampsfrom an inoperative position to an operative position with its center ofillumi- 22 nation at the focal point of said lens, each of said lamps atits operative position having its longitudinl axis of symmetry at asubstantial angle to the aXis of said lens, whereby a lens of minimumsize permitting lamp interchange may be used with said lampchangingapparatus.

JOHN R. MACKAY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

